Diesteramide plasticizers



United States Patent F 3,340,218 DIESTERAMIDE PLASTICIZERS Frank C.Magne, Robert R. Mod, and Evald L. Skau, New Orleans, La., assignors tothe United States of America as represented by the Secretary ofAgriculture No Drawing. Original application Jan. 22, 1963, Ser. No.263,370. Divided and this application Mar. 1, 1966, Ser. No. 549,078

3 Claims. (Cl. 260-31.6)

Ser. No. 263,370, which was a divi- 1961, now United This application isa division of filed Jan. 22, 1963 (now abandoned), sion of Ser. No.147,377, filed Oct. 24, States Patent No. 3,179,615.

A non-exclusive, irrevocable, royalty-free license in the inventionherein described, throughout the world for all purposes of the UnitedStates Government, with the power to grant sublicenses for suchpurposes, is hereby granted to the Government of the United States ofAmerica.

This invention relates to a plastic composition, the plasticizercomponent of which is a novel class of amides. The amides which form theplasticizer component of the resinous composition which is subject ofthis invention have the ability to plasticize both the hydrophilic andthe hydrophobic type of resins and in addition are characterized bytheir ability to confer softening characteristics on nitrile rubbers.

It is known to prepare amides of the type represented by the formula 0 OCHaCHrO-il R RC-N CHaCHr-O-(fiR' where R and R are the same substituentalkyl group (particularly a saturated alkyl group with chain length offrom 2 to 9 carbon atoms). These amides have recognized utility asplasticizers for vinyl-chloride-type resins, but it is well known thatwhenever the length of the carbon chain in the substitutent alkyl groupsexceeds 8 or 9 carbon atoms, i.e., when R==R'=C,,H and n exceeds 9,compatibility with the vinyl-chloride-type resins is lost. It is knownthat compounds of the formula are incompatible of R=R'=CH or'of R=R'= along chain monounsaturated alkyl group such as C H We have found thatcompounds of this formula are-also incompatible if R==CH and R is a longchain saturated alkyl such as C H or if 'R'=CH and R is a long chainpolyunsaturated alkyl such as C H We have made the surprising discovery,however, that compounds of this formula are compatible if R=CH and R iseither a long chain monounsaturated alkyl group such as C H or a longchain saturated or monounsaturated alkyl group containing at least oneepoxy group such as C H O or r'z si 3,340,218 Patented Sept. 5, 1967 iceIt is the object of this invention to supply amides of the typerepresented by the formula wherein -R is an alkyl group of chain lengthC to C the alkyl group being monounsaturated and/or epoxidized, i.e.,containing only one olefinic group and/or at least one epoxy group. Rmay also be phenyl, cyclohexyl, a substituted phenyl such as C H COCR",where R" represents a saturated alkyl group of less than about 9 carbonatoms.

It is also the object of this invention to supply mixtures of amidesrepresented by this formula consisting predominantly of diesteramides inwhich R represents an alkyl group (or alkyl groups) of chain length C toC these alkyl groups being monounsaturated and/or monounsaturatedcontaining at least one oxirane ring and/ or saturated containing atleast one oxirane ring, and R' is a saturated alkyl group containing 3or less carbon atoms.

These diesteramides are efiicient primary solvent-type plasticizersexhibiting good compatibility with, and imparting long-term thermalstability, low volatility, and low brittle point to polymer andcopolymer compositions of vinyl chloride. The diesteramides are also,quite unexpectedly, eflicient plasticizers for cellulose triacetate andin addition they possess utility as softeners for nitrile rubbers. Theterm vinyl chloride resins is used throughout this specification and theaccompanying claims to refer to polymers and copolymers of monomerscontaining vinyl chloride in a predominant proportion in parts byweight. The terms such as good compatibility, compatible, and compatibleplasticizers in reference to plasticizers for vinyl chloride resins areused throughout the specification to refer to plasticizers which show nosigns of exudation or migration to the surface for at least 30 days whenthe plasticizer is present in the proportion of about 60 parts per 100parts by weight of vinyl chloride resin.

.The term long chain fatty acid is used throughout this specificationand the accompanying claims to refer to monocarboxylic aliphatic acidscontaining 12 or more carbon atoms.

The compatible diesteramides are primary plasticizers and act ascompatibilizers for incompatible diesteramides. For example, the binarycompositions where is composed of oleoyl25% palmitoyl or epoxyoleoy1-15%palmitoyl and in which R is CH, are compatible, as are all proportionsof these two binary mixtures. Ternary compositions can tolerate evenlarger proportions of palmitoyl than would be expected; e.g., the 30%palmitoyl-35% epoxyoleoyl35% oleyl mixture is fully compatible. Thus,mixtures of long chain fatty acids or esters can be used to preparecompatible diesteramides providing there is a predominance ofmonoolefinic, epoxy-saturated, or epoxymonoolefinic long chain fattyacids individually or in combination in the mixture. The fatty acidsobtained from cottonseed oil consist roughly of 27% of saturated (mostlypahnitic) acid, 27% of monounsaturated (oleic) acid, and 46% ofpolyunsaturated (linoleic) acid. The diesteramides prepared fromcottonseed oil acids are incompatible because of the large proportion ofsaturated and polyunsaturated alkyl groups in the mixture. Compatiblediesteramides can, however, be prepared from cottonseed oil acids whichhave been modified either by converting the polyunsaturated acyls in themixture to monounsaturated acyls by selective hydrogenation,dimerization, halogenation, and epoxidation, or by converting thepolyunsaturated acyls alone or both the polyunsaturated and themonounsaturated acyls to saturated epoxyacyls. Similar adjustments incomposition can be made in the fatty acid mixtures obtainable from othernatural sources, such as vegetable or animal oils and fats, tall oil,and the like, to prepare compatible diesteramides. These adjustments ofthe degree of unsaturation may be performed on the original oils, on theacids, on the esters, or on the diesteramides prepared from them. Ingeneral it is usually preferred to perform the epoxidation at thediesteramide stage.

- The amides which are the subject of this invention we shall refer toas diesteramides and they can be prepared as We shall show presently ina variety of ways. These diesteramides, which carry two substituentalkyl groups; e.g., two methyl groups and one substituent alkyl group ofchain length exceeding 11 carbon atoms which substituent group may bemonounsaturated and/or epoxidized are, as noted above, unexpectedlycompatible with vinylchloride type resins. When the long-chain alkylsubstituent is monounsaturated, complete compatibility with vinyl typeresins exists up through chain lengths of C Additionally, if the longchain alkyl substituent group is an epoxy containing saturated ormonounsaturated group,

compatibility with vinyl chloride type resins extends through C chainlengths.

The diesteramides which are the subject of this invention can beprepared by the following sequential reactions. First, an alkanolaminesuch as diethanolamine is reacted with the alkyl ester; e.g., the methylester, of a long-chain fatty acid. This initial reaction is anester-exchange type of reaction and is carried out in the presence of analkoxide catalyst; e.g., sodium methoxide. If the alkanolamine used isdiethanolamine, an N-bis(2-hydroxyethyl) amide of a fatty acid isformed. The product of this first reaction is subsequently reacted withthe acid anhydride or the acid chloride of an acid such as acetic,propionic, benzoic, hexahydrobenzoic acid, or of the monoester ofdibasic acids such as phthalic or succinic acids or of the diesters oftribasic acids such as phosphoric acid. Acetic or benzoic acid is thepreferred acid to esterify the two hydroxyl groups present. Thediesteramides prepared by the aforementioned sequence of reactions, weshall refer to as symmetrical diesteramides prepared by the directedmethod.

Other alkanolamines which may be used instead of diethanolamine aredialkanolamines such as di-isopropanolamine (1,l'-imino-di-2-propanol),3,3-iminodipr0- panol, and the like.

It is possible, alternatively, to prepare diesteramides by reactingsimultaneously all the components (the dialkanolamine and the two fattyacids of different chain lengths). The result of this alternativeprocess wherein all of the'reaction components are present'at the sametime in the reaction mixture produces what We shall refer to hereinafteras the mixed diesteramides produced by the undirected method. Since thereaction is a random one, the precise location of the various alkylsubstituents is not known and cannot be predicted with certainty as itcan with the directed reaction method. Mixed diesteramides couldpossibly contain all of the following disteramides:

where X represents the moiety Example I N-bz's(2-acetoxyethyl) oleamideTwo hundred and ninety-six grams (1 mole) of methyl oleate was slowlyadded to a vigorously stirred mixture of 105 grams (1 mole) ofdiethanolamine and 3.6 grams (0.15 mole) of metallic sodium dissolved inabsolute methanol. The reaction was carried out with continued stirringat 65 to 75 C. and at 60 millimeters pressure. It is necessary to addthe methyl oleate slowly so as to control frothing of the reactionmixture. The reaction was complete after all the methyl oleate had beenadded and the evolution of methanol had ceased. The product of thisreaction was N-bis(2-hydroxyethyl)oleamide. To 124 grams (approximately0.34 mole) of N-bis (2-hydroxyethyl)oleamide from the above reaction wasslowly added with stirring grams (0.78 mole) of acetic anhydride. Thereaction temperature was maintained at 70 to 75 C. during and for anadditional 30 minutes subsequent to the addition of the aceticanhydride. The reaction product was taken up in commercial hexane,washed free of acetic acid with water, and stripped of hexane. Analysisof the I stripped product showed 3.09% nitrogen. The theoreticalnitrogen content for N-bis (2-acetoxyethyl)oleamide is 3.09%. Thismaterial was tested as a plasticizer for vinyl chloride resin (seeSample No. 1A in Table I).

A separate fraction of the diesteramide prepared as above was distilledin a short-path still at 0.3 millimeter pressure and a small fractionboiling at 188 C. was rejected. The main distillation-cut, boiling atabout 219 C., was tested as a plasticizer for vinyl chloride resin (seeSample No. 1B in TableI).

Example 2.-N-bis(Z-benzoyloxyethyl)oleamio'e To 33 grams (0.10 mole) ofN-bis(2-hydroxyethyl)oleamide, prepared as shown in Example 1 andisolated from the reaction mixture by the addition of a slight excess ofglycolic acid followed by extraction with hexane, washing and stripping,was added 30.8 grams (0.22 mole) of benzoyl chloride. The reaction wascarried out in 33 grams of benzene. The temperature was raised slowlyand mainatined at 80 C. for two hours following which time 17.3 7

Example 3.N-bis(2-acet0xyethyl) linoleamide This material was preparedby the method of Example -1, substituting methyl linoleate for themethyl oleate. The isolated product gave a nitrogen analysis of 2.87%(theory 3.10%). It was tested as a vinyl chloride resin plasticizer (seeSample No. 3 in Table I).

Example 4.-N-bis(2-acetoxyethyl)amide of cottonseed oil fatty acids Thismaterial was prepared by the method of Example 1, using the methylesters of cottonseed oil fatty acids instead of methyl oleate. (Themethyl esters were derived from cottonseed oil fatty acids having aniodine value (I.V.) of 113 and a neutralization equivalent of 273.) Thisproduct gave a nitrogen analysis of 3.10% (theory 3.15%). It was testedas a plasticizer for vinyl chloride resin (see Sample No. 4 in Table I).

Example 5.N-bis(2-acetoxyethyl)amide of selectively hydrogenatedcottonseed oil fatty acids This material was prepared by the method ofExample 1 using the methyl esters of selectively hydrogenated cottonseedoil fatty acids instead of methyl oleate. (The selectively hydrogenatedcottonseed oil fatty acids had an IV. of 73.2, a thiocyanogen value of68.0, and a neutralization equivalent of 274.) The product had an IV. of44.9 and gave a nitrogen analysis of 3.05% (theory 3.14% It was testedas a vinyl chloride resin plasticizer (see Sample No. 5 in Table I).

The product, N-bis(2-acetoxyethyl)amide of the hydrogenated cottonseedacids, was tested as a plasticizer for cellulose triacetate (41%acetyl). This composition, cast as a film from a mixture of 30 parts ofdiesteramide and 100 parts of cellulose triacetate in acetone solvent,was flexible, clear, nongreasy, and withstood repeated flexing along asharp crease without cracking. This is a compatible composition.

Example 6.N-bis(2-acetoxyethyl)epoxyoleamide 0.077 mole of the productfrom Example 3 was dissolved in 50 grams of chloroform and added slowlyto 192 grams of a chloroform solution of perbenzoic acid, containing11.7 grams (0.085 mole) of perbenzoic acid, while maintaining atemperature of to 5 C. The reaction mixture was allowed to stand at 0 C.for 24 hours. The N-bis(2-acetoxyethyl)epoxyoleamide was extracted witha volume of diethyl ether equal to two times that of the reactionmixture. The extract was washed free of any benzoic acid, and the etherstripped off. The product had a nitrogen content of 2.73% (theory 2.99%)and an oxirane-oxygen content of 3.74% (theory 3.42%). It was tested asa plasticizer for vinyl chloride resin (see Sample No. 6 in Table I).

Example 7.-N-bis(2 '-acet0xyethyl)amide of partially epoxidizedcottonseed oil fatty acids The product of Example 4 was partiallyepoxidized with perbenzoic acid by the process described in Example 6.In this instance the ratio of perbenzoic acid to amide was 0.056 to0.077 mole. The oxirane-oxygen content of the product was 2.35%. Theproduct was tested as a plasticizer for vinyl chloride resin (see SampleNo. 7 in Table 1).

Example 8.-N-bis(2-acetoxyethyl)amide of completely epoxidized rapeseedfatty acids The N-bis(2-acetoxyethyDamide of rapeseed acids was preparedby the method of Example 1 except that the methyl esters of rapeseedfatty acids were used in place of methyl oleate. This product had anI.V. of 73.8 and a nitrogen content of 2.69% (theory 2.94%). It wasevalulated as a vinyl chloride resin plasticizer and found to beincompatible. It was epoxidized by the procedure of Example 7 to anoxirane content of 3.93% using 1.3 moles of perbenzoic acid .per mole ofamide. The epoxidized product was tested as a vinyl chloride resinplasticizer (see Sample No. 8 in Table 1).

Example 9.Mixed diesteramides (undirected process) of selectivelyhydrogenated cottonseed oil acids and acetic acid 0.20 mole ofdiethanolamine, 0.40 mole of glacial acetic acid, 0.205 mole of theselectively hydrogenated cottonseed acids described in Example 5, and 25ml. of benzene were refluxed in an oil bath at a temperature of 200 C.until there was no further evolution of water. (This was ascertained byobserving the watercollected in the Dean-Stark trap.) The reactionproduct was cooled,

Example 10.Mixed diesteramides of oleic and acetic acids The sameprocedure and the same molar proportions of reactants were used as inExample 9, except that oleic acid was used instead of the hydrogenatedcottonseed acids. This product gave a nitrogen analysis of 2.71%

' (theory 3.09%). It was tested as a vinyl chloride resin plasticizer(see Sample No. 10 in Table 1).

Example 11.--Mixed diesteramides of epoxidized cottonseed oil acids andacetic acid The same procedure and the same molar proportions ofreactants were used as in Example 9 except that the cottonseed oil fattyacids described in Example 4 were used instead of the hydrogenatedcottonseed oil fatty acids. This product gave a nitrogen analysis of2.73% (theory 3.14%). It was partially epoxidized using the same processand molar proportions of amide and perbenzoic acid as shown in Example7. The end product had an oxirane-oxygen content of 1.58%. It was testedas a vinyl chloride resin plasticizer (see Sample No. 11 in Table I) Thevarious diesteramides were tested as plasticizers for vinylchloride-vinylacetate (95.5) copolymer resin (Vinylite VYDR) in thefollowing formulation:

Percent Vinyl chloride resin 63.5 Diesteramide' I s 35.0 Stearic acid0.5 Basic lead carbonate 1.0

This formulation for each diesteramide sample was Parts Nitrile rubber100.0 SRF black 60.0 Zinc oxide 5.0 Stearic acid 1.5 Sulfur 1.5Benzothiaz yldisulfide 1.5 Softener 20.(

These compositions were cured for 30 minutes at 310 F. TheN-bis(2-acetoxyethyl) amides of the hydrogenater and partiallyepoxidized cottonseed oil acids preparer in Examples 5 and 7,respectively, were found to bl acceptable compatible softeners fornitrile rubber, show ing no signs of spewing in 30 days. The testresults to these compositions are shown as Samples 5 and 7, respectively, in Table II.

TABLE I Tensile 100% Elonga- Brittle Volatil- Compati- Sampe Nostrength, Modulus, tion, point, ity loss, bility p s.i. p.s.i. Percent0. Percent l C=compatib1e; I=incompatib1e.

TALBE II Tensile Strength Elongation 300% Modulus Sample N 0. Shore AWeight Brittle Volume Hardness, loss, point, change, Unaged, Aged,Unaged, Aged, Unaged, Aged, 10 see. percent C. percent p.s.i. p.s.i.percent percent p.s.i. p.s.i.

We claim: 30 3. The vinyl chloride resin composition of claim 1 1. Avinyl chloride resin composition wherein wherein the plasticizer isN-bis(2-benzoyloxyethyl)ole- (a) the resin is selected from the groupconsisting of amide.

homopolymers of vinyl chloride and copolymers of References Citedvinylchloride with vinyl acetate in which the vinyl UNITED STATESPATENTS chloride 1s m a predormnant amount, and 35 2143 765 1/1939Dickey et al 1 6 b a lasticizer for said resin re resented b the 7 g f Py 2,253,064 9/1941 D1ckey et a1. 106-186 2,862,959 12/1958 Patrick eta1. 260=31.8 H 3,179,615 4/1965 Magne et al. 26030.4 O CHrCHz-O-C-R' 40J L OTHER REFERENCES wherein the plasticizer isN-bis(2eacetoxyethyl)oleamide.

Magne et al.: Some N-Disubstituted Amides of Long- Chain Fatty Acids asVinyl Plasticizers; Industrial Engineering Chemistry, vol. 50, pp. 617,618; 1958.

JULIUS FROME, Primary Examinerr MORRIS LIEBMAN, Examiner.

L. T. JACOBS, Assistant Examiner.

1. A VINYL CHLORIDE RESIN COMPOSITION WHEREIN (A) THE RESIN IS SELECTEDFROM THE GROUP CONSISTING OF HOMOPOLYMERS OF VINYL CHLORIDE ANDCOPOLYMERS OF VINYL CHLORIDE WITH VINYL ACETATE IN WHICH THE VINYLCHLORIDE IS IN A PREDOMINANT AMOUNT, AND (B) A PLASTICIZER FOR SAIDRESIN REPRESENTED BY THE FORMULA